Nearly 50 million Americans smoke, and it's burning a hole in employers' wallets. Smoking leads to $75.5 billion every year in direct health-care costs, according to the Centers for Disease Control and Prevention.

Smokers with individually written health-care policies already pay more for health insurance, but companies are starting to require smoking employees in group plans to pay more, too. "The premium increase is becoming more of a trend," says Micah Berman, executive director of the Tobacco Public Policy Center, a legal resource center in Columbus, Ohio, working to reduce smoking and tobacco use.

Will employers start asking employees with other habits and conditions-for example, drinking and obesity--to pay more for health insurance, too? Nan Andrews Amish, a San Francisco Bay-area health-care consultant, thinks so. "We are moving toward asking the overweight to pay more," she says.

Tread carefully when applying surcharges within a group plan, however. Nondiscrimination rules of the Health Insurance Portability and Accountability Act prohibit companies with group plans from assessing surcharges on employees with certain health factors. "Nicotine addiction is considered a health factor," Berman says.

Employers can charge more, however, if rate hikes are done in conjunction with a wellness program. "If an employer can make a good-faith showing that higher insurance surcharges for tobacco users are part of an overall wellness program," Berman says, "they can legally charge higher health insurance premiums for these employees."

Chris Penttila is a freelance journalist in the Chapel Hill, North Carolina, area.